Fortunately, one of the problems I have avoided with my RT-340 is burn back and the associated flash fire. My theory is that using LavaLock seals on both the cooking chamber and pellet hopper lids slows, or stops, enough air flow into those chambers to prevent the problem. YMMV
I do reduce the heat to 250F or less before turning the grill off and I’m sure that also helps.
I do reduce the heat to 250F or less before turning the grill off and I’m sure that also helps.